U.S. patent application number 17/706738 was filed with the patent office on 2022-09-29 for wavelength conversion device, light source device, and projector.
The applicant listed for this patent is SEIKO EPSON CORPORATION. Invention is credited to Toshiaki HASHIZUME.
Application Number | 20220308433 17/706738 |
Document ID | / |
Family ID | 1000006257675 |
Filed Date | 2022-09-29 |
United States Patent
Application |
20220308433 |
Kind Code |
A1 |
HASHIZUME; Toshiaki |
September 29, 2022 |
WAVELENGTH CONVERSION DEVICE, LIGHT SOURCE DEVICE, AND
PROJECTOR
Abstract
A wavelength. conversion device includes a motor having a
rotation axis and a hollow space, a wavelength converter converting
incident first light in a first wavelength band to second light in
a second wavelength band that is different from the first
wavelength band, and a coupling member thermally coupled to the
wavelength converter. At least a part of the coupling member is
arranged in the hollow space. The motor changes a position of
incidence of the first light on the wavelength converter relatively
with respect to the wavelength converter.
Inventors: |
HASHIZUME; Toshiaki;
(Okaya-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SEIKO EPSON CORPORATION |
Tokyo |
|
JP |
|
|
Family ID: |
1000006257675 |
Appl. No.: |
17/706738 |
Filed: |
March 29, 2022 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G03B 21/16 20130101;
G02B 26/008 20130101; G03B 21/204 20130101; G03B 21/208
20130101 |
International
Class: |
G03B 21/20 20060101
G03B021/20; G02B 26/00 20060101 G02B026/00; G03B 21/16 20060101
G03B021/16 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 29, 2021 |
JP |
2021-054821 |
Claims
1. A wavelength conversion device comprising: a motor having a
rotation axis and a hollow space; a wavelength converter converting
incident first light in a first wavelength band to second light in
a second wavelength band that is different from the first
wavelength band; and a coupling member thermally coupled to the
wavelength converter, wherein at least a part of the coupling
member is arranged in the hollow space, and the motor changes a
position of incidence of the first light on the wavelength
converter relatively with respect to the wavelength converter.
2. The wavelength conversion device according to claim 1, further
comprising an optical element condensing the first light onto the
wavelength converter, wherein an optical axis of the optical
element and the rotation axis are shifted from each other.
3. The wavelength conversion device according to claim 2, wherein
the motor rotates the optical element about the rotation axis, and
the optical axis of the optical element, an optical axis of the
first light incident on the optical element, and the rotation axis
are shifted from each other.
4. The wavelength conversion device according to claim 3, wherein
the motor has a rotor part and a stator part rotating the rotor
part about the rotation axis, and the optical element is supported
by the rotor part.
5. The wavelength conversion device according to claim 1, wherein
the wavelength converter is arranged in the hollow space.
6. The wavelength conversion device according to claim 1, wherein
the motor rotates the wavelength converter about the rotation axis,
and an optical axis of the first light incident on the wavelength
converter and the rotation axis are shifted from each other.
7. The wavelength conversion device according to claim 6, further
comprising an optical element condensing the first light onto the
wavelength converter, wherein an optical axis of the optical
element and the rotation axis are shifted from each other.
8. The wavelength conversion device according to claim 7, wherein
the optical axis of the first light incident on the wavelength
converter and the optical axis of the optical element substantially
coincide with each other.
9. The wavelength conversion device according to claim 6, further
comprising a heat radiation member thermally coupled to the
coupling member, wherein the coupling member and the heat radiation
member are rotated with the wavelength converter by the motor, and
at least a part of the heat radiation member is arranged outside
the motor.
10. The wavelength conversion device according to claim 6, further
comprising: a heat radiation member thermally coupled to the
coupling member; and a heat transfer member arranged between the
coupling member and the heat radiation member, wherein at least a
part of the heat radiation member is provided outside the
motor.
11. The wavelength conversion device according to claim 10, wherein
the coupling member is rotated with the wavelength converter by the
motor, and the heat radiation member does not rotate and is
fixed.
12. The wavelength conversion device according to claim 10, wherein
the heat transfer member is a thermally conductive grease.
13. The wavelength conversion derive according to claim 10, wherein
the heat radiation member has a recess provided at a face of the
heat radiation member, the face facing the coupling member, and the
recess holds the heat transfer member.
14. The wavelength conversion device according to claim 6, further
comprising a substrate supporting the wavelength converter, wherein
the motor has a rotor part and a stator part rotating the rotor
part about the rotation axis, and the substrate is supported by the
rotor part.
15. A light source device comprising: a light source emitting first
light; and the wavelength conversion device according to claim 1,
on which the first light emitted from the light source is
incident.
16. A projector comprising: the light source device according to
claim 15; a light modulator modulating light emitted from the light
source device; and an optical projection device projecting the
light modulated by the light modulator.
Description
[0001] The present application is based on, and claims priority
from JP Application Serial Number 2021-054821, filed Mar. 29, 2021,
the disclosure of which is hereby incorporated by reference herein
in its entirety.
BACKGROUND
1. Technical Field
[0002] The present disclosure relates to a wavelength conversion
device, a light source device, and a projector.
2. Related Art
[0003] According to the related art, a light source device having a
solid-state light source, a phosphor wheel that converts the
wavelength of excitation light emitted from the solid-state light
source and emits fluorescence, and a motor) that rotates the
phosphor wheel, is known. WO2016/05625 is an example of this
device.
[0004] The phosphor wheel described in WO2016/056285 has a
disk-like substrate, a phosphor layer formed at one surface of the
substrate, a reflection film provided between the substrate and the
phosphor layer, and a heat radiation structure having a plurality
of heat radiation fins. When excitation light enters the phosphor
layer, the phosphor layer absorbs a part of the excitation light
and emits light in a predetermined wavelength range. The phosphor
layer generates heat when excited by the excitation light to emit
light. As the temperature of the phosphor layer rises, the
fluorescence conversion efficiency of the phosphor layer drops. To
cope with this, the motor rotationally drives the phosphor wheel to
change the position irradiated with the excitation light on the
phosphor layer with time, thus restraining the temperature rise at
the irradiated position. The heat of the phosphor layer is
transferred to the heat radiation structure via the substrate and
is thus radiated.
[0005] However, in the phosphor wheel described in WO2016/056285,
the heat radiation structure is provided at the outside of the
motor in a radial direction about the rotation axis of the motor.
This poses a problem in that the phosphor wheel tends to be large.
Also, as the solid-state light source emits blue laser light to the
phosphor, the high energy of the blue laser light causes optical
dust collection and thus poses a problem of dust adhering to the
phosphor layer and the condensing lens. To cope with this, the
phosphor wheel is covered by a casing to achieve dust-proofness.
However, sealing, the phosphor wheel poses a problem in that the
heat is trapped in the casing.
[0006] Therefore, a configuration of a wavelength conversion device
that can be configured in a small size is desired.
SUMMARY
[0007] A wavelength conversion device according to a first aspect
of the present disclosure includes a motor having a rotation axis
and a hollow space, a wavelength converter converting incident
first light in a first wavelength band to second light in a second
wavelength band that is different from the first wavelength band,
and a coupling member thermally coupled to the wavelength
converter. At least a part of the coupling member is arranged in
the hollow space. The motor changes a position of incidence of the
first light on the wavelength converter relatively with respect to
the wavelength converter.
[0008] A light source device according to a second aspect of the
present disclosure includes a light source emitting first light and
the wavelength conversion device according to the first aspect, on
which the first light emitted from the light source is
incident.
[0009] A projector according to a third aspect of the present
disclosure includes the light source device according to the second
aspect, a light modulator modulating light emitted from the light
source device, and an optical projection device projecting the
light modulated by the light modulator.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is schematic view showing the configuration of a
projector according to a first embodiment.
[0011] FIG. 2 is a schematic view showing the configuration of a
light source device in the first embodiment.
[0012] FIG. 3 is a schematic showing the configuration of a
wavelength conversion device in the first embodiment.
[0013] FIG. 4 is a schematic view showing the configuration of the
wavelength conversion device in the first embodiment.
[0014] FIG. 5 is a schematic view showing the configuration of a
wavelength conversion device of a light source device provided in a
projector according to a second embodiment.
[0015] FIG, 6 is a schematic view showing the configuration of a
wavelength conversion device of a light source device provided in a
projector according to a third embodiment.
[0016] FIG. 7 is a schematic view showing the configuration of a
wavelength conversion device of a light source device provided is a
projector according to a fourth embodiment.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
First Embodiment
[0017] A first embodiment of the present disclosure will now be
described with reference to the drawings.
Schematic Configuration of Projector
[0018] FIG. 1 is a schematic view showing the configuration of a
projector 1 according to this embodiment.
[0019] The projector 1 according to this embodiment modulates light
emitted from a light source device 4A, described later, thus forms
an image corresponding to image information, and projects the
formed image in an enlarged form on a projection target surface
such as a screen. As shown in FIG. 1, the projector 1 has an
exterior casing 2 and an image projection device arranged inside
the exterior casing 2. Although not illustrated, the projector 1
also has a control device that controls operations of the projector
1, a power supply device that supplies electric Power to an
electronic component forming the projector 1, and a cooling device
that cools a cooling target forming the projector 1.
Configuration of Exterior Casing
[0020] The exterior casing 2 forms the exterior of the projector 1.
The exterior casing 2 accommodates the image projection device 3,
the control device, the power supply device, and the cooling
device. The exterior casing 2 has a top face part and a bottom face
part, not illustrated, a front face part 21, a back face part 22, a
left side face part 23, and a right side face part 24, and is
formed substantially in the shape of a rectangular
parallelepiped.
[0021] The front face part 21 has an opening 211 to expose a part
of an optical projection device 36, described later. An image
projected by the optical projection device 36 passes through the
opening 211. The front face part 21 also has an outlet port 212
through which a cooling gas that has cooled a cooling target inside
the projector 1 is discharged out of the exterior casing 2. The
right side face part 24 has an inlet port 241 through which a gas
outside the exterior casing 2 is introduced inside as a cooling
gas.
Configuration of Image Projection Device
[0022] The image projection device 3 forms and projects an image
corresponding to image information. The image projection device 3
has the light source device 4A, a homogenization device 31, a color
separation device 32, a relay device 33, an image forming device
34, an optical component casing 35, and the optical projection
device 36.
[0023] The light source device 4A emits light. The configuration of
the light source device 4A will be described in detail later.
[0024] The homogenization device 31 homogenizes the light emitted
from the light source device 4A. The light homogenized by the
homogenization device 31 goes through the color separation device
32 and the relay device 33 and illuminates a modulation area of a
light modulator 343, described later, in the image forming device
34. The homogenization device 31 has two lens arrays 311, 312, a
polarization converter 313, and a superimposing lens 314.
[0025] The color separation device 32 separates the light incident
from the homogenization device 31 into red, green, and blue color
lights. The color separation device 32 has two dichroic mirrors
321, 322, and a reflection mirror 323 reflecting the blue light
separated by the dichroic mirror 321.
[0026] The relay device 33 is provided on the optical path of the
red light, which is longer than the optical path of the blue light
and the optical path of the green light, and thus restrains the
loss of the red light. The relay device 33 has a light
incident-side lens 331, a relay lens 333, and reflection mirrors
332, 334.
[0027] In this embodiment, the relay device 33 is provided on the
optical path of the red light. However, this is not limiting. For
example, the blue light may be used as the color light having a
longer optical path than the other color lights, and the relay
device 33 may be provided on the optical path of the blue
light.
[0028] The image forming device 34 modulates the incident red,
green, and blue color lights, combines the modulated color lights
together, and thus forms an image to be projected by the optical
projection device 36. The image forming device 34 has three field
lenses 341 provided corresponding to the incident color lights,
three light incident-side polarizers 342, three light modulators
343, three light exiting-side polarizers 344, and one light
combining device 345.
[0029] The light modulator 343 modulates the light emitted from the
light source device 41 according to image information. The three
light modulators 343 include a light modulator 343R modulating the
red light, a light modulator 343E modulating the green light, and a
light modulator 343B modulating the blue light. In this embodiment,
the light modulator 343 is formed of a transmission-type liquid
crystal panel. The light incident-side polarizer 342, the light
modulator 343, and the light exiting-side polarizer 344 together
form a liquid crystal light valve.
[0030] The light combining device 345 combines together the color
lights modulated by the Light modulators 343B, 343G, 3438 and thus
forms an image. In this embodiment, the light combining device 345
is formed of a cross dichroic prism. However, this is not limiting.
For example, the light combining device 345 can be formed of a
plurality of dichroic mirrors.
[0031] The optical component casing 35 accommodates the
homogenization device 31, the color separation device 32, the relay
device 33, and the image forming device 34 inside. In the image
projection device 3, an illumination optical axis Ax, which is an
optical axis in design, is set. The optical component casing 35
holds the homogenization device 31, the color separation device 32,
the relay device 33, and the image forming device 34 at
predetermined positions on the illumination optical axis ASK. The
light source device 4A and the optical projection device 36 are
arranged at predetermined positions on the illumination optical
axis Ax.
[0032] The optical projection device 36 projects the image incident
from the image forming device 34 in an enlarged form on the
projection target surface. That is, the optical projection device
36 projects the lights modulated by the light modulators 343E,
343G, 343R. The optical projection device 36 is formed, for
example, as a lens set having a plurality of lenses accommodated in
a cylindrical lens barrel.
Configuration of Light Source Device
[0033] FIG. 2 is a schematic view showing the light source device
4A.
[0034] The light source device 4A emits illumination light LT
illuminating the light modulator 343, to the homogenization device
31. As shown in FIG. 2, the light source device 4A has a light
source casing 41, a light source unit 42 accommodated inside the
light source casing 41, an afocal optical element 43, a first phase
difference element 44, a homogenizer optical element 45, a light
separation element 46, a second phase difference element 47, a
condensing element 48, a diffuse reflection element 49, a third
phase difference element 50, and a wavelength conversion device
6A.
[0035] In the description below, a +X-direction, a +Y-direction,
and a +Z-direction are employed as three directions orthogonal to
each other. Of the three directions, the +X-direction is the
direction in which the light source device 4A emits the
illumination light LT. Although not illustrated, the opposite
direction of the +X-direction is a -X-direction. The opposite
direction of the +Y-direction is a -Y-direction. The opposite
direction of the +Z-direction is a -Z-direction.
Configuration of Light Source Casing
[0036] The light source casing 41 is a sealed casing which dust or
the like does not easily enter, and is formed substantially in the
shape of a rectangular parallelepiped. The light source casing 41
has a front face 411, a back face 412, a right side face 413, and a
left side face 414. The light source casing 41 also has a top face
coupling together the end parts in the +Y-direction of the front
face 411, the back face 412, the right side face 413, and the left
side face 414, and a bottom face coupling together the end parts in
the -Y-direction, though not illustrated.
[0037] The front face 411 is a face from which the illumination
light LT is emitted, of the light source casing 41. The front face
411 is arranged in the +Z-direction in the light source casing 41.
The front face 411 has an exit port 415 through which the
illumination light LT is emitted.
[0038] The back face 412 is a face opposite to the front face 411
and is arranged in the -Z-direction in relation to the front face
411. The wavelength conversion device 6A is attached to the back
face 412.
[0039] In the light source casing 41, an illumination optical axis
Ax1 along the +X-direction and an illumination optical axis Ax2
along the +Z-direction are set. That is, the illumination optical
axis Ax1 and the illumination optical axis Ax2 intersect each
other.
[0040] The light source unit 42, the afocal optical element 43, the
first phase difference element 44, the homogenizer optical element
45, the light separation element 46, the second phase difference
element 47, the condensing element 48, and the diffuse reflection
element 49 are arranged on the illumination optical axis Ax1.
[0041] The wavelength conversion device 6A, the light separation
element 46, and the third phase difference element 50 are arranged
on the illumination optical axis Ax2. The light separation element
46 is arranged at the part where the illumination optical axis Ax1
and the illumination optical axis Ax2 intersect each other.
[0042] Configuration of Light Source Unit
[0043] The light source unit 42 has a light source 421 emitting
light, and a collimating lens 424.
[0044] The light source 421 has a plurality of solid-state
light-emitting elements 422 and a light source support member
423.
[0045] The solid-state light-emitting element 422 is a solid-state
light source emitting s-polarized blue light, which is excitation
light. More specifically, the solid-state light-emitting element
422 is a semiconductor laser, and the blue light emitted from the
solid-state light-emitting element 422 is, for example, laser light
having a peak wavelength of 440 nm. In this case, s-polarized light
is s-polarized light to the light separation element 46 and
p-polarized light is p-polarized to the light separation element
46.
[0046] The light source support member 423 supports the plurality
of solid-state light-emitting elements 422 arranged in an
array-like form on a plane orthogonal to the illumination optical
axis Ax1. The light source support member 423 is a thermally
conductive metal member and is attached to the right side face 413
intersecting the illumination optical axis Ax1. Therefore, the heat
of the plurality of solid-state light-emitting elements 422 is
transferred to the light source casing 41 via the light source
support member 423.
[0047] The blue light emitted from the plurality of solid-state
light-emitting elements 422 is converted into a parallel luminous
flux by the collimating lens 424 and enters the afocal optical
element 43.
[0048] In this embodiment, the light source 421 emits blue light
that is linearly polarized light having the same direction of
polarization. However, this is not limiting. The light source 421
may be configured to emit s-polarized blue light and p-polarized
blue light. In this case, the first phase difference element 44 can
be omitted.
Configuration of Afocal Optical Element
[0049] The afocal optical element 43 adjusts the diameter of the
luminous flux of the blue light incident from the light source unit
42. The afocal optical element 43 is formed of a lens 431
condensing incident light and a lens 432 parallelizing the luminous
flux condensed by the lens 431. The afocal optical element 43 may
be omitted.
Configuration of First Phase Difference Element
[0050] The first phase difference element 44 is provided between
the afocal optical element 43 and the homogenizer optical element
45. The first phase difference element 44 converts the incident
blue light, which is one type of linearly polarized light, into
light including s-polarized blue light Ls and p-polarized blue
light Lp. The first phase difference element 44 may be rotationally
moved about an axis of rotational movement along the illumination
optical axis An by a rotational movement device. In this case, the
proportion of the blue light Ls and the blue light Lp in the
luminous flux emitted from the first phase difference element 44
can be adjusted according to the angle of rotational movement of
the first phase difference element 44.
Configuration of Homogenizer Optical Element
[0051] The homogenizer optical element 45 homogenizes the
illuminance distribution of the blue lights Ls, Lp incident via the
first phase difference element 44. The homogenizer optical element
45 is formed of a pair of multi-lens arrays 451, 452.
[0052] Also, a diffuse transmission element that diffuses the
incident light in the course of transmitting the incident light and
thus homogenizes the illuminance distribution of the exiting light
may be employed instead of the homogenizer optical element 45. The
diffuse transmission element can employ, for example, a
configuration having a hologram, a configuration where a plurality
of small lenses are arrayed on a plane orthogonal to the optical
axis, and a configuration where a surface through which the light
passes is a rough surface.
Configuration of Light Separation Element
[0053] The blue lights Ls, Lp having passed through the homogenizer
optical element 45 enter light separation element 46.
[0054] The light separation element 46 is a prism-type polarizing
beam splitter and separates the s-polarized light component and the
p-polarized light component included in the incident light.
Specifically, the light separation element 46 reflects the
s-polarized light component and transmits the p-polarized light
component. Therefore, the blue light Is, which is the s-polarized
light incident in the +X-direction, is reflected into the
-Z-direction by the light separation element 46 and enters the
wavelength conversion device 6A. Meanwhile, the blue light to,
which is the p-polarized light incident in the +X-direction, is
transmitted through the light separation element 46 in the
+X-direction and enters the second phase difference element 47. The
light separation element 46 also has a color separation
characteristic of reflecting light with a wavelength shorter than a
predetermined wavelength and transmitting light with the
predetermined wavelength or longer, for both the s-polarized light
component and the p-polarized light component. Therefore, the blue
light Ls incident along the -Y-direction from the second phase
difference element 47 is reflected into the +Z-direction by the
light separation element 46 and enters the third phase difference
element 50. Meanwhile, fluorescence YL incident in the +Z-direction
from the wavelength conversion device 6A is transmitted through the
light separation element 46 in the +Z-direction and enters the
third phase difference element 50.
[0055] The light separation element 46 may have the function of a
half mirror transmitting a part of the light incident from the
light source unit 42 via the homogenizer optical element 45 and
reflecting the rest of the light, and the function of a dichroic
mirror reflecting the blue light incident from the diffuse
reflection element 49 and transmitting the fluorescence YL incident
from the wavelength conversion device 6A. In this case, the first
phase difference element 44 can be omitted.
Configuration of Wavelength Conversion Device
[0056] The wavelength conversion device 6A converts first light in
a first wavelength band emitted from the light source 421 to second
light in a second wavelength band that is different from the first
wavelength band. That is, the wavelength conversion device 6A
converts the blue light Ls incident in the -Z-direction to the
fluorescence YL and emits the fluorescence YL in the +Z-direction.
The blue light Ls is equivalent to the first light in the first
wavelength band. The fluorescence YL is equivalent to the second
light in the second wavelength band that is different from the
first wavelength band. More specifically, the wavelength conversion
device 6A is excited by the incidence of the blue light Ls as
excitation light and emits the fluorescence YL having a longer
wavelength than the wavelength of the incident blue light Ls. The
fluorescence YL is, for example, light having a peak wavelength of
500 to 700 nm. That is, the fluorescence YL includes green light
and red light.
[0057] The configuration of the wavelength conversion device 6A
will be described fa detail later.
Configuration of Second Phase Difference Element and Condensing
Element
[0058] The second phase difference element 47 is arranged between
the light separation element 46 and the condensing element 48. The
second phase difference element 47 converts the blue light Lp
having passed through the light separation element 46 to circularly
polarized blue light Lc. The blue light Lc enters the condensing
element 48.
[0059] The condensing element 48 condenses the blue light Lc
incident from the second phase difference element 47, onto the
diffuse reflection element 49. The condensing element 48 also
parallelizes the blue light Lc incident from the diffuse reflection
element 49. The number of lenses forming the condensing element 48
can be changed according to need.
Configuration of Diffuse Reflection Element
[0060] The diffuse reflection element 49 reflects and diffuses the
incident blue light Lc at a diffusion angle similar to that of the
fluorescence YL emitted from the wavelength conversion device 6A.
For example, the diffuse reflection element 49 reflects the blue
light Lc incident in the +X-direction into the -X-direction by
Lambertian reflection. The diffuse reflection element 49 may be
rotated about a rotation axis parallel to the illumination optical
axis Ax1.
[0061] The blue light Lc diffuse-reflected by the diffuse
reflection element 49 passes through the condensing element and
subsequently enters the second phase difference element 47. When
reflected by the diffuse reflection element 49, the blue light Lc
is converted to circularly polarized light with the direction of
rotation reversed. Therefore, the blue light Lc incident on the
second phase difference element 47 via the condensing element 48 is
converted to s-polarized blue light Ls by the second phase
difference element 47. The blue light Ls is reflected by the light
separation element 46 and enters the third phase difference element
50. That is, the light incident on the third phase difference
element 50 from the light separation element 46 is white light that
is a mixture of the blue light Ls and the fluorescence YL.
Configuration of Third Phase Difference Element
[0062] The blue light Ls reflected in the +Z-direction by the light
separation element 46 and the fluorescence YL having passed through
the light separation element 46 in the +Z-direction enter the third
phase difference element 50. That is, white light formed of the
blue light Ls and the fluorescence YL combined together at the
light separation element 46 enters the third phase difference
element 50.
[0063] The third phase difference element 50 converts the incident
white light to light formed of a mixture of s-polarized light and
p-polarized light. The white illumination light LT thus converted
enters the homogenization device 31.
Configuration of Wavelength Conversion Device
[0064] FIG. 3 is a schematic view showing the configuration of the
wavelength conversion device 6A. FIG. 3 shows an example of a beam
of the blue light Ls incident on an outer part 21 of an optical
element 61.
[0065] The wavelength conversion device 6A is a reflection-type
wavelength converter that converts the blue light is incident along
the -Z-direction to the fluorescence YL and emits the fluorescence
YL to the blue light Ls-incident side, as described above. As shown
in FIG. 3, the wavelength conversion device GA has the optical
element 61, a wavelength converter 62, a coupling member 63, a heat
radiation member 64, and a hollow motor 65.
Configuration of Optical Element
[0066] The optical element 61 condenses the blue light Es reflected
by the light separation element 46, onto the wavelength converter
62. The optical element 61 also parallelizes the fluorescence YL
incident from the wavelength converter 62 and emits the
parallelized fluorescence YL to the light separation element 46. In
the example shown in FIG. 3, the optical element 61 is formed of
one lens. However, any number of lenses may be employed to form the
optical element 61. When the optical element 61 is formed of a
plurality of lenses, all of the plurality of lenses may be rotated
by the hollow motor 65, or at least one lens including the nearest
lens to the wavelength converter 62, of the plurality of lenses,
may be rotated.
Configuration of Wavelength Converter
[0067] The wavelength converter 62 converts the first light in the
first wavelength band to the second light in the second wavelength
band. That the wavelength converter 62 converts the wavelength of
the blue light Ls incident from the optical element 61 and emits
the fluorescence YL, which is the converted light. In this
embodiment, the wavelength converter 62 is a reflection-type
wavelength converter emitting the fluorescence YL to the blue light
Ls-incident side.
[0068] The wavelength converter 62 has a wavelength conversion
layer 621 and a reflection layer 623.
[0069] The wavelength conversion layer 621 includes a phosphor
generating the fluorescence YL having a longer wavelength than the
wavelength of the blue light Ls. The fluorescence YL is, for
example, light having a peak wavelength of 500 to 700 nm and
includes green light and red light. The fluorescence YL is an
example of the second light in the second wavelength band that is
different from the first wavelength band. The surface in the
+Z-direction of the wavelength conversion layer 621 is a light
incident surface 622 on which the blue light Ls is incident. That
is, the wavelength converter 62 has the light incident surface 622
on which the blue light Ls is incident.
[0070] The light incident surface 622 intersects an optical axis X1
of the optical element 61 and a rotation axis Rx of the optical
element 61 by the hollow motor 65. In this embodiment, the rotation
axis Rx intersects the center of the light incident surface 622, as
viewed from the +Z-direction. The meaning of the rotation axis Rx
intersecting the center of the light incident surface 622 includes
the case where the rotation axis Rx intersects substantially the
center of the light incident surface 622. However, this is not
limiting. The rotation axis Rx may intersect any part of the light
incident surface 622.
[0071] Meanwhile, the position of intersection between the light
incident surface 622 and the optical axis X1 of the optical element
61 and the position of intersection between the light incident
surface 622 and the rotation axis Rx are spaced apart from each
other. That is, the optical axis X1 and the rotation axis Rx are
spaced apart from each other on the light incident surface 622. On
a surface orthogonal to the optical axis X1 of the optical element
61, the distance between the optical axis X1 and the rotation axis
Rx is shorter than the distance between the rotation axis Er and an
optical axis X2 of the blue light Ls emitted from the light
separation element 46. However, this is not limiting. It suffices
that the optical axis X1, the optical axis X2, and the rotation
axis Ra are spaced apart from each other. Either one of the
distance between the optical axis X1 and the rotation axis Rx and
the distance between the optical axis X2 and the rotation axis Rx
may be longer than the other.
[0072] In this embodiment, the wavelength conversion layer 621 is
formed in a substantially rectangular shape, as viewed from the
+Z-direction. However, this is riot limiting. The wavelength
conversion layer 621 may be formed in a substantially circular
shape or in a ring shape, as viewed from the +Z-direction.
[0073] The reflection layer 623 is Provided to the opposite side of
the wavelength conversion layer 621 from the blue light Ls-incident
side. That is, the reflection layer 623 is provided in the
-Z-direction in relation to the wavelength conversion layer 621.
The reflection layer 623 reflects the light incident from the
wavelength conversion layer 621 into the +Z-direction. The
reflection layer 623 is a part coupled to the coupling member 63,
of the wavelength converter 62.
[0074] The fluorescence YL emitted in the +Z-direction from the
wavelength converter 62 enters the optical element 61. The
fluorescence YL incident on the optical element 61 is parallelized
by the optical element 61 and is emitted to the light separation
element 46. The fluorescence YL incident on the light separation
element 46 passes through the light separation element 46 and
enters the third phase difference element 50.
Configuration of Coupling Member
[0075] The coupling member 63 is thermally coupled to the
wavelength converter 62. The coupling member 63 has a support part
631 supporting the wavelength converter 62, and a coupling part 632
coupled co the back face 412 of the light source casing 41.
[0076] The support part 631 is arranged in a hollow space SP
provided inside the hollow motor 65. That is, a part of the
coupling member 63 is arranged in the hollow space SP. The face in
the +direction of the support part 631 is a support face 631A
supporting the wavelength converter 62. Specifically, the support
face 631A is coupled to the reflection layer 623 of the wavelength
converter 62 by a solder or the like. The heat of the wavelength
converter 62 is transferred to the support part 631. In this way,
the coupling member 63 also functions as a support body supporting
the wavelength converter 62.
[0077] The coupling part 632 is integrated with the support part
631. A face 632A in the +Z-direction of the coupling part 632 is
thermally coupled to the outer surface of the back face 412. In
this case, the coupling part 632 is fixed in such a way as to cover
an opening 416 provided in the back face 412, from outside the
light source casing 41. Therefore, the sealability of the light
source casing 41 is secured. The opening 416 is, for example, an
opening for arranging the wavelength converter 62 inside the light
source casing 41.
Configuration of Heat Radiation Member
[0078] The heat radiation member 64 is provided at the opposite
side of the coupling part 632 of the coupling member 63 from the
wavelength converter 62. That is, the heat radiation member 64 is
arranged outside the light source casing 41. The heat radiation
member 64 radiates the heat of the wavelength converter 62
transferred from the coupling member 63, at the outside of the
light source casing 41. The heat radiation member 64 has a
plurality of fins 641. A cooling gas circulated by a cooling device
circulates between the plurality of fins 641. The plurality of fins
641 transfer the heat of the wavelength converter 62 to the cooling
gas and thus radiate the heat of the wavelength converter 62. As
such a heat radiation member 64 is attached to the outer surface of
the back face 412, the sealability inside the light source casing
41 is secured.
Configuration of Hollow Motor
[0079] The hollow motor 65 changes the position of incidence of the
blue light Ls, which is the first light, on the wavelength
converter 62, relatively to the wavelength converter 62.
Specifically, the hollow motor 65 rotates the optical element 61
about the rotation axis Rx parallel to the optical axis X1 of the
optical element 61 and thus changes the position of incidence of
the blue light Ls emitted from the optical element 61 and entering
the light incident surface 622.
[0080] The hollow motor 65 has a rotor part 651, a stator part 652,
and a fluid bearing, not illustrated, which is provided between the
rotor part 651 and the stator part 652.
[0081] The rotor part 651 is an annular part rotating about the
rotation axis Rx in the hollow motor 65. The rotor part 651 rotates
about the rotation axis Rx. That is, the hollow motor 65 has the
rotation axis Rx, and the rotor part 651 has an opening 6511 in a
circular shape about the rotation axis Rx, as viewed from the
4-Z-direction.
[0082] The optical element 61 is attached to the rotor part 651 via
an attachment member AT. Specifically, the optical element 61 is
provided at the face in the +Z-direction of the rotor part 651,
that is, at the face intersecting the rotation axis hr. As the
rotor part 651 rotates about the rotation axis Rx relatively to the
stator part 652, the optical element 61 rotates about the rotation
axis Rx.
[0083] The stator part 652 is a part rotating the rotor part 651.
The stator part 652 is formed in an annular shape about the
rotation axis Rx. That is, the stator part 652 has an opening 6521
in a circular shape about the rotation axis Pr, as viewed from the
+Z-direction. The opening 6521 and the opening 6511 communicate
with each other, thus providing the hollow space SP inside the
hollow motor 65. That is, the hollow motor 65 has the hollow space
SP formed by the opening 6511 and the opening 6521.
[0084] In this embodiment, the stator part 652 is fixed to the
inner surface of the back face 412. However, this is not limiting.
The stator part 652 may be fixed to another component.
[0085] The hollow motor 65 may be a bearing instead of a fluid
bearing.
Effects of Wavelength Conversion Device
[0086] When the rotor cart 651 is rotated, the optical element 61
attached to the rotor part 651 rotates about the rotation axis Ra
of the hollow motor 65.
[0087] The rotation axis Ra of the hollow motor 65 and the optical
axis X1 of the optical element 61 do not coincide with each other.
That is, the optical element 61 is provided eccentrically in
relation to the rotation axis Rx. The optical axis X2 of the blue
light Ls incident on the optical element 61 from the light
separation element 46 does not change even when the optical element
61 is rotated by the hollow motor 65.
[0088] Also, the focal point of the optical element 61 located on
the optical axis X1 is not located on the light incident surface
622 of the wavelength converter 62 and is located at the blue light
Ls-incident side of the light incident surface 622 or at the
opposite side of the light incident surface 622 from the blue light
Ls-incident side. In this embodiment, the focal point of the
optical element 61 is located at the opposite side of the light
incident surface 622 from the blue light Is-incident side.
[0089] Therefore, with a change in the position of incidence of the
blue light Ls at a light incident surface 61A on which the blue
light Ls is incident, of the optical element 61, the position of
incidence of the blue light Ls on the light incident surface 622 of
the wavelength converter 62 changes.
[0090] For example, as shown in FIG. 3, when the blue light Ls
enters the outer part P1 in relation to the optical axis X1 of the
optical element 61, the blue light Ls is refracted by the optical
element 61 and is condensed to the optical axis X1 side. Since the
focal point of the optical element 61 is located at the opposite
side of the light incident surface 622 from the blue light
Is-incident side, the blue light Ls enters the opposite side of the
rotation axis Rx on the light incident surface 622, as viewed from
the +Z-direction. In the example shown in FIG. 3, the blue light Ls
incident on the outer part Pi in the +X-direction in relation to
the rotation axis Rx, of the optical element 61, enters a part in
the -X-direction in relation to the rotation axis Rx, of the light
incident surface 622, as viewed from the +Z-direction.
[0091] As described above, the wavelength converter 62 is arranged
in such a way that the rotation axis Rx intersects the center of
the light incident surface 622, as viewed from the
+Z-direction.
[0092] FIG. 4 shows an example of a beam of the blue light Ls
incident on an inner part P2 closer to the optical axis X1 than the
outer part P1 of the optical element 61.
[0093] Meanwhile, when the optical element 61 is rotated by the
hollow motor 65 and the blue light Ls enters the inner part P2
closer to the optical axis X1 of the optical element 61 than the
outer part P1 of the optical element 61, the blue light Ls enters a
part in the +X-direction in relation to the rotation axis Rx, of
the light incident surface 622, as viewed from the +Z-direction, as
shown in FIG. 4.
[0094] As the optical element 61 condensing the blue light Ls
incident from the light separation element 46 onto the wavelength
converter 62 is thus rotated about the rotation axis Rx spaced
apart from the optical axis X1 of the optical element 61 by the
hollow motor 65, the position of incidence of the blue light Ls on
the light incident surface 622 of the wavelength converter 62 can
be changed. Specifically, the position of incidence of the blue
light Ls on the light incident surface 622 can be moved circularly.
Thus, constant and continuous incidence of the blue light Ls on a
part of the light incident surface 622 can be restrained and
therefore the generation of a site with a locally high temperature
in the wavelength converter 62 can be restrained. Therefore, a drop
in the efficiency of conversion from the blue light. T,s to the
fluorescence YL in the wavelength converter 62 can be
restrained.
[0095] In this embodiment, the relative position between the
optical element 61 and the wavelength converter 62 is decided in
such a way that the area of the circular shape where the position
of incidence of the blue light Ls moves is twice the shape of the
focal point of the blue light Ls by the optical element 61 or more,
and eight times or less. Also, the amount of eccentricity of the
optical element 61 in relation to the rotation axis Rx is 0.5 times
the shape of the focal point or more and twice or less. The number
of rotations of hollow motor 65 is 500 rpm or more.
[0096] However, the area of the circular shape where the position
of incidence of the blue light Ls moves, the amount of eccentricity
of the optical element 61 in relation to the rotation axis Rx, and
the number of rotations of the hollow motor 65 are not limited to
the above examples.
Effects of First Embodiment
[0097] The above-described projector 1 according to this embodiment
achieves the effects described below.
[0098] The projector 1 has the light source device 4A, the light
modulator 343, and the optical projection device 36. The light
modulator 343 modulates light emitted from the light source device
4A according to image information. The optical projection device 36
projects the light modulated by the light modulator 343.
[0099] The light source device 4A has the wavelength conversion
device 6A and the light source 421 emitting the blue light Ls
incident on the wavelength conversion device 6A. The blue light Ls
is equivalent to the first light in the first wavelength band.
[0100] The wavelength conversion device 6A has the wavelength
converter 62, the coupling member 63, and the hollow motor 65. The
wavelength converter 62 converts the incident blue light Ls to the
fluorescence YL. The fluorescence YL is equivalent to the second
light in the second wavelength band that is different from the
first wavelength band. The coupling member 63 is thermally coupled
to the wavelength converter 62. In the hollow motor 65, the
rotation axis Rx and the hollow space SP are provided. A part of
the coupling member 63 is provided in the hollow space 55. The
hollow motor 65 changes the position of incidence of the blue light
Ls on the wavelength converter 62 relatively to the wavelength
converter 62.
[0101] Such a configuration can restrain continuous local incidence
of the blue light Ls on the wavelength converter 62. Therefore, the
generation of a part with a locally high temperature in the
wavelength converter 62 can be restrained and a drop in the
efficiency of conversion from the blue light Ls to the fluorescence
YL in the wavelength converter 62 can be restrained.
[0102] Also, at least a part of the coupling member 63 thermally
coupled to the wavelength converter 62 is provided inside the
hollow space SP provided in the hollow motor 65. Therefore, a path
to transfer the heat of the wavelength converter 62 can be provided
inside the hollow space SP. Thus, the wavelength conversion device
6A can be miniaturized, compared with the case where a path to
transfer the heat of the wavelength converter 62 is provided
outside the hollow motor 65.
[0103] The light source device 4A having such a wavelength
conversion device 6A can stably emit light. The projector 1 can
stably project the light modulated by the light modulator 343, that
is, an image.
[0104] The wavelength conversion device 6A has the optical element
61 condensing the blue light Ls onto the wavelength converter 62.
The optical axis X1 of the optical element 61, the optical axis X2
of the blue light Ls incident on the optical element 61, and the
rotation axis Rx are spaced apart from each other on a plane
orthogonal to the rotation axis Rx (a plane intersecting the
rotation axis Rx). The hollow motor 65 rotates the optical element
61 about the rotation axis Rx.
[0105] In such a configuration, when the optical element is rotated
by the hollow motor 65, the position of incidence of the blue light
Ls on the optical element 61 changes in the radial direction of the
optical element 61. Thus, the direction of emission of the blue
light Ls from the optical element 61 can be changed and therefore
the position of incidence of the blue light Ls on the wavelength
converter 62 can be changed. Accordingly, a drop in the efficiency
of conversion from the blue light Ls to the fluorescence YL in the
wavelength converter 62 can be restrained, as described above.
[0106] in the wavelength conversion device 6A, the focal point of
the optical element 61 is located at the opposite side of the
wavelength converter 62 from the blue light Ls-incident side, on
the optical axis X1 of the optical element 61.
[0107] In such a configuration, when the optical element 61 is
rotated, the position of incidence of the blue light Ls on the
wavelength converter 62 with the direction of emission from the
optical element 61 changed, can be changed. Thus, a drop in the
efficiency of conversion from the blue light Ls to the fluorescence
YL in the wavelength converter 62 can be restrained.
[0108] In the wavelength conversion device 6A, the hollow motor 65
has the rotor part 651 and the stator part 652 rotating the rotor
part 651 about the rotation axis Rx. The optical element 61 is
supported by the rotor part 651.
[0109] In such a configuration, the optical element 61 can be
rotated about the rotation axis Rx of the hollow motor 65. Also,
the optical element 61 can be easily arranged in such a way that
the optical axis X1 of the optical element 61 and the rotation axis
Rx are spaced apart from each other.
Second Embodiment
[0110] A second embodiment of the present disclosure will now be
described.
[0111] A projector according to this embodiment has a configuration
similar to that of the projector 1 according to the first
embodiment but differs in the configuration of the light source
device. In the description below, a part that is the same or
substantially the same as an already described part is denoted by
the same reference sign and is not described further in detail.
[0112] FIG. 5 is a schematic view showing a part of the
configuration of a light source device 4E provided in the projector
according to this embodiment.
[0113] The projector according to this embodiment has a
configuration and functions similar to those of the projector 1
according to the first embodiment except for having the light
source device 4B shown in FIG. 5 instead of the light source device
4A according to the first embodiment.
[0114] The light source device 4B has a configuration and functions
similar to those of the light source device 4A except for having a
condensing element 51 and a wavelength conversion device 6B instead
of the wavelength conversion device 6A according to the first
embodiment.
Configuration of Condensing Element
[0115] The condensing element 51 is arranged between the light
separation element 46 and the wavelength conversion device 6B on
the illumination optical axis Ax2. Similarly to the optical element
61, the condensing element 51 condenses the blue light Ls, which is
the first light incident in the -Z-direction from the light
separation element 46, onto the wavelength converter 62. The
condensing element 51 also condenses the fluorescence YL emitted in
the +Z-direction from the wavelength converter 62 and emits the
parallelized fluorescence YL in the direction toward the light
separation element 46.
[0116] The condensing element 51 is arranged in such a way that an
optical axis X3 of the condensing element 51 substantially
coincides with the optical axis X2 of the blue light Ls incident
from the light separation element 46. The condensing element 51 is
also arranged in such a way that the optical axis X3 of the
condensing element 51 is spaced apart from the rotation axis Rx of
the hollow motor 65 of the wavelength conversion device 6B. That
is, the optical axis X3 of the condensing element 51 is spaced
apart from the rotation axis Rx on a plane orthogonal to the
rotation axis Rx (a plane intersecting the rotation axis Rx). The
focal point of the condensing element 51 is located on the light
incident surface 622 of the wavelength converter 62, on the optical
axis X3.
Configuration of Wavelength Conversion Device
[0117] The wavelength conversion device 6B converts the incident
blue light Ls to the fluorescence it, similarly to the wavelength
conversion device 6A according to the first embodiment.
Specifically, the wavelength conversion device 6B converts the blue
light Ls incident from the light separation element 46 to the
fluorescence YL.
[0118] The wavelength conversion device 6B has a configuration and
functions similar to those of the wavelength conversion device 6A
except, for having a substrate 66 instead of the optical element 61
and except that the hollow motor 65 rotates the substrate 66
instead of the optical element 61. That is, the wavelength
conversion device 6B has the wavelength converter 62, the coupling
member 63, the heat radiation member 64, the hollow motor 65, and
the substrate 66.
[0119] The substrate 66 is attached to the rotor part 651 of the
hollow motor 65, in the state of supporting the wavelength
converter 62 at the face in the +Z-direction. In other words, in
the wavelength conversion device 6B, the rotor part 651 of the
hollow motor 65 supports the wavelength converter 62.
[0120] The substrate 66 is formed of a material with good thermal
conductivity such as a metal in a plate-like shape and is fixed to
the face in the +Z-direction of the rotor Part 651. Therefore, when
the rotor part 651 is rotated about the rotation axis Rx, the
wavelength converter 62 supported by the substrate 66 is rotated
about the rotation axis Rx.
[0121] The coupling member 63 is coupled to the face in the
-Z-direction of the substrate 66. A part of the coupling member 63
is arranged in the hollow space SP. The face 632A in the
+Z-direction of the coupling part 632 of the coupling member 63 is
spaced apart from the back face 412 the -Z-direction. The coupling
member 63 is coupled to the heat radiation member 64 provided
outside the hollow motor 65. Therefore, when the rotor part 651 as
rotated, the wavelength converter 62 supported by the substrate 66,
and the coupling member 63 and the heat radiation member 64 coupled
to the substrate 66, are rotated about the rotation axis Rx in a
unified manner.
[0122] Since the coupling member 63 is rotated by the hollow motor
65, there is a gap between the back face 412 and the face 632A
facing the back face 412, of the coupling member 63. This gap
communicates with the hollow space SP via the opening 416.
Therefore, in the light source device 4B, the sealability of the
light source casing 41 is secured by the fluid bearing or the
bearing between the rotor part 651 and the stator part 652.
[0123] In this embodiment, the rotation axis Rx of the hollow motor
65 intersects the center of the light incident surface 622, as
viewed from the blue light Ls-incident side, that is, as viewed
from the +Z-direction. The meaning of the rotation axis Rx
intersecting the center of the light incident surface 622 includes
the case where the rotation axis Rx intersects substantially the
center of the light incident surface 622.
[0124] The light incident surface 622 also intersects the optical
axis X3 of the condensing element 51.
Effects of Wavelength Conversion Device
[0125] When the rotor part 651 is rotated, the wavelength converter
62 supported by the substrate 66 attached to the rotor part 651
rotates about the rotation axis Rx.
[0126] In this example, the rotation axis Rx does not coincide with
the optical axis X2 of the blue light Ls incident on the condensing
element 51 and the optical axis X3 of the condensing element 51 in
other words, the rotation axis Rn is eccentric from the optical
axes X2, X3. The optical axis X2 of the blue light Ls and the
optical axis X3 of the condensing element 51 substantially coincide
with each other. That is, the focal point of the condensing element
51 is located on the light incident surface 622 on the optical axes
X2, X3, which do not coincide with the rotation axis Rx. The
optical axis X2 of the blue light Ls does not change even when the
wavelength converter 62 is rotated by the hollow motor 65.
[0127] Therefore, when the wavelength converter 62 is rotated, the
position of incidence of the blue light Ls on the light incident
surface 622 changes. Specifically, when the wavelength converter 62
is rotated, the position of incidence of the blue light Ls on the
light incident surface 622 continuously moves with time in a
circumferential direction about the rotation axis Rx. The
trajectory of the position of incidence of the blue light Ls is a
ring-shape about the position of intersection with the rotation
axis Rx on the light incident surface 622.
[0128] As the wavelength converter 62 is thus rotated about the
rotation axis Rx by the hollow motor 65, the position of incidence
of the blue light Ls on the light incident surface 622 can be
changed. Thus, constant and continuous incidence of the blue light
Ls on a part of the light incident surface 622 can be restrained
and therefore the generation of a part with a locally high
temperature in the wavelength converter 62 can be restrained.
Therefore, a drop in the efficiency of conversion from the blue
light Ls to the fluorescence YL in the wavelength converter 62 can
be restrained.
[0129] Since the wavelength converter 62 is provided outside the
hollow space SP, incidence on the hollow motor of the Fluorescence
YL emitted from the side face intersecting the light incident
surface 622, of the wavelength converter 62, can be restrained.
Thus, a temperature rise in the hollow motor 65 can be
restrained.
Effects of Second Embodiment
[0130] The above-described projector according to this embodiment
achieves the effects described below, in addition to effects
similar to those of the projector 1 according to the first
embodiment.
[0131] In the wavelength conversion device 6B, the optical axis X2
of the blue light Ls incident on the wavelength converter 62 is
spaced apart from the rotation axis Rx on a plane orthogonal to the
rotation axis Rx (a plane intersecting the rotation axis Rx). The
hollow motor 65 rotates the wavelength converter 62 about the
rotation axis Rx.
[0132] In such a configuration, since the optical axis X2 of the
blue light Is incident on the wavelength converter 62 is spaced
apart from the rotation axis Rx, the position of incidence of the
blue light Ls on the wavelength converter 62 continuously changes
about the rotation axis Rx when the wavelength converter 62 is
rotated by the hollow motor 65. That is, the position of incidence
of the blue light Ls on the wavelength converter 62 continuously
changes with time in a circumferential direction about the rotation
axis Rx. Thus, the generation of a part with a locally high
temperature in the wavelength converter 62 can be restrained and a
drop in the efficiency of conversion from the blue light Ls to the
fluorescence YL in the wavelength converter 62 can be
restrained.
[0133] The wavelength conversion device 6B has the heat radiation
member 64 thermally coupled to the coupling member 63. The heat
radiation member 64 is rotated with the wavelength converter 62 by
the hollow motor 65. The heat radiation member 64 is provided
outside the hollow motor 65.
[0134] In such a configuration, the heat of the wavelength
converter 62 can be transferred to the heat radiation member 64 via
the coupling member 63. Since the heat radiation member 64 is
provided outside the hollow motor 65, the heat of the wavelength
converter 62 can be radiated outside the hollow motor 65. Also,
since the heat radiation member 64 is rotated with the wavelength
converter 62 by the hollow motor 65, the radiation of the heat of
the wavelength converter 62 by the heat radiation member 64 can be
facilitated. Thus, the wavelength converter 62 can be cooled
effectively.
[0135] The wavelength conversion device 6B has the substrate 66
supporting the wavelength converter 62. The hollow motor 65 has the
rotor part 651 and the stator part 652 rotating the rotor part 651
about the rotation axis Rx. The substrate 66 is supported by the
rotor part 651.
[0136] In such a configuration, the wavelength converter 62 can be
rotated about the rotation axis Rx.
Third Embodiment
[0137] A third embodiment of the present disclosure will now be
described.
[0138] A projector according to this embodiment has a configuration
similar to that of the projector according to the second embodiment
but differs from the projector according to the second embodiment
in the configuration of the wavelength conversion device forming
the light source device. In the description below, a part that is
the same or substantially the same as an already described part is
denoted by the same reference sign and is not described further in
detail.
[0139] FIG. 6 is a schematic view showing a part of the
configuration of a light source device 4C provided in the projector
according to this embodiment.
[0140] The projector according to this embodiment has a
configuration and functions similar to those of the projector
according to the second embodiment except for having the light
source device 4C shown in FIG. 6 instead of the light source device
4B according to the second embodiment.
[0141] The light source device 4C has a configuration and functions
similar to those of the light source device 4B except for having a
wavelength conversion device 6C instead of the wavelength
conversion device 6B according to the second embodiment.
Configuration of Wavelength Conversion Device
[0142] The wavelength conversion device 6C converts the incident
blue light Ls to the fluorescence YL, similarly to the wavelength
conversion devices 6A, 6B according to the first and second
embodiments. Specifically, the wavelength conversion device 6C
converts the blue light Ls incident from the light separation
element 46 to the fluorescence YL.
[0143] The wavelength conversion device 6C has a configuration and
functions similar to those of the wavelength conversion device 6B
except for having a coupling member 67, a heat transfer member 68,
and a heat radiation member 69, instead of the coupling member 63
and the heat radiation member 64. That is, the wavelength
conversion device 6C has the wavelength converter 62, the hollow
motor 65, the substrate 66, the coupling member 67, the heat
transfer member 68, and the heat radiation member 69.
[0144] The coupling member 67 is arranged in the hollow space SP
provided inside the hollow motor 65 The coupling member 67 is
coupled to the face in the -Z-direction of the substrate 66,
similarly to the coupling member 63 That is, the coupling member 67
is rotated about the rotation axis Rx along with the wavelength
converter 62 and the substrate 66 by the hollow motor 65 The
coupling member 67 is thermally coupled to the heat radiation
member 69. Specifically, the coupling member 67 is coupled to the
heat radiation member 69 via the heat transfer member 68. The
substrate 66 is coupled to the wavelength conversion layer 621,
which rises in temperature, via the reflection layer 623. The
wavelength conversion layer 621, when formed of a ceramic, has a
coefficient of linear expansion of 1.times.10.sup.-6 or lower.
Therefore, a sintered compact of sliver-molybdenum,
copper-molybdenum, diamond-copper or the like having a high thermal
conductivity and a low coefficient of linear expansion can be used
as the substrate 66.
[0145] The coupling member 67 transfers the heat transferred
thereto from the wavelength converter 62 via the substrate 66, to
the heat radiation member 69 via the heat transfer member 68.
[0146] The heat transfer member 68 transfers the heat transferred
thereto from the coupling member 67, to the heat radiation member
69. The heat transfer member 68 is configured to be able to
transfer the heat to the heat radiation member 69 fixed to the
light source casing 41 even when the coupling member 67 is rotated.
In this embodiment, the heat transfer member 68 is formed of a
thermally conductive grease.
[0147] The heat radiation member 69 radiates the heat of the
wavelength converter 62 transferred from the heat transfer member
68. The heat radiation member 69 has a fixing part 691, a heat
transfer part 692, and a plurality of fins 693.
[0148] The fixing part 691 is a part fixing the heat radiation
member 69 to the light source casing 41. The fixing part 691 is
fixed in such a way that the face in the +Z-direction of the fixing
part 691 is thermally coupled to the outer surface of the back face
412 and in such a way as to close the opening 416 at the outside of
the light source casing 41.
[0149] The heat transfer part 692 protrudes substantially
cylindrically from the face in the +Z-direction of the fixing part
691. The heat transfer part 692 is thermally coupled to the
coupling member 67 via the heat transfer member 68. That is, the
heat of the wavelength converter 62 is transferred to the heat
transfer part 692 via the substrate 66, the coupling member 67, and
the heat transfer member 68. In this embodiment, a gap of 1 .mu.m
or larger and 5 .mu.m or smaller is provided in the +Z-direction
between the coupling member 67 and the heat transfer part 692, and
the heat transfer member 68 is installed between the coupling
member 67 and the heat transfer part 692. As the heat transfer
member 68, for example, a thermally conductive grease such as
silicone oil that has a thermal conductivity of 0.1 W/mK or higher
and a high viscosity and that evaporates in as small an amount as
possible at 150.degree. C. or below, is selected.
[0150] At a face 692A in the +Z-direction of the heat transfer part
692, a plurality of very smell recesses 6921 are provided. The
recesses 6921 form a spiral in such a direction that the heat
transfer member 68 moves axially inward when the coupling member 67
is rotated. The depth of the recesses 6921 is 2 .mu.m. The recesses
6921 can be formed by plating the coupling member 67, then
performing surface grinding, and subsequently cutting and etching
or the like. The recesses 6921 thus hold the heat transfer member
68. In this way, the state where the heat transfer member 68 is
held between the coupling member 67 and the heat transfer part 692
can be maintained. Also, recesses similar to the recesses 6921 may
be provided at the face opposite to the face 692A, of the coupling
member 67. Moreover, a sealing part that restrains leakage and
scattering of the heat transfer member 68 may be provided at least
at one of the coupling member 67 and the heat transfer part 692.
For example, an O-ring may be provided at an outer circumferential
part of the heat transfer member 68.
[0151] The plurality of fins 693 protrude from the face in the
-Z-direction of the fixing part 691. The plurality of fins 693 are
arranged outside the light source casing 41 and radiate the heat of
the wavelength converter 62 transferred to the heat transfer part
692, outside the light source casing 41.
Effects of Wavelength Conversion Device
[0152] In the wavelength conversion device 6C, as the wavelength
converter 62 is rotated about the rotation axis Rx by the hollow
motor 65, the position of incidence of the blue light Ls on the
light incident surface 622 can be continuously changed with time,
as in the wavelength conversion device 6B according to the second
embodiment. Thus, constant and continuous incidence of the blue
light Ls on a part of the light incident surface 622 can be
restrained and therefore the generation of a part with a locally
high temperature in the wavelength converter 62 can be restrained.
Therefore, a drop in the efficiency of conversion from the blue
light Ls to the fluorescence YL in the wavelength converter 62 can
be restrained.
[0153] In the wavelength conversion device 6C, the components to be
rotated by the hollow motor 65 are the wavelength converter 62, the
substrate 66, and the coupling member 67. That is, in the
wavelength conversion device 6C, the hollow motor 65 does not
rotate the heat radiation member 69 having a relatively large
dimension and a heavy weight. Thus, the weight of the components to
be rotated by the hollow motor 65 can be reduced and the rotation
load on the hollow motor 65 can be reduced. Therefore, a
small-sized hollow motor with a small torque can be employed as the
hollow motor 65 and the wavelength conversion device 6C can be
configured in a small size. Thus, the light source device 4C and
hence the projector can be miniaturized.
Effects of Third Embodiment
[0154] The above-described projector according to this embodiment
achieves the effects described below, in addition to effects
similar to those of the projector according to the second
embodiment.
[0155] The wavelength conversion device 6C has the heat radiation
member 69 thermally coupled to the coupling member 67, and the heat
transfer member 68 provided between the coupling member 67 and the
heat radiation member 69. A part of the heat radiation member 69 is
provided outside the hollow motor 65. The other part of the heat
radiation member 69 is arranged inside the hollow space SP.
[0156] In such a configuration, the heat generated in the
wavelength converter 62 can be transferred to the heat radiation
member 69 partly arranged outside the hollow motor 65, via the
coupling member 67 and the heat transfer member 68. Since the heat
of the wavelength converter 62 can be radiated outside the hollow
motor 65, the wavelength converter 62 can be cooled
effectively.
[0157] In the wavelength conversion device 6C, the heat transfer
member 68 is a thermally conductive grease.
[0158] In such a configuration, even when the heat radiation member
69 is fixed, the heat of the wavelength converter 62 can be
transferred to the heat radiation member 69 from the coupling
member 67 rotating with the wavelength converter 62, via the heat
transfer member 68. Therefore, the heat of the wavelength converter
62 can be efficiently transferred to the heat radiation member
69.
[0159] In the wavelength conversion device 6C, the heat radiation
member 69 has the recesses 6921, which are provided at the face
692A facing the coupling member 67 and hold the heat transfer
member 68.
[0160] In such a configuration, the state where the heat transfer
member 68 is held between the coupling member 67 and the heat
radiation member 69 can be maintained. Thus, the thermally coupled
state between the coupling member 67 and the heat radiation member
69 can be maintained.
Fourth Embodiment
[0161] A fourth embodiment of the present disclosure will now be
described.
[0162] A projector according to this embodiment has a configuration
similar to that of the projector according to the third embodiment
but differs in the arrangement of the substrate 66. In the
description below, a part that is the same or substantially the
same as an already described part is denoted by the same reference
sign and is not described further in detail.
[0163] FIG. 7 is a schematic view showing a part of the
configuration of a light source device 4D provided in the projector
according to this embodiment.
[0164] The projector according to this embodiment has a
configuration and functions similar to those of the projector
according to the third embodiment except for having the light
source device 4D shown in FIG. 7 instead of the light source device
4C according to the third embodiment.
[0165] The light source device 4D has a configuration and functions
similar to those of the light source device 4B or the light source
device 4C except for having a wavelength conversion device 6D
instead of the wavelength conversion device 6B according to the
second embodiment or the wavelength conversion device 6C according
to the third embodiment.
[0166] The wavelength conversion device 6D converts the incident
blue light Ls to the fluorescence YL, similarly to the wavelength
conversion devices 6A, 6B, 6C. Specifically, the wavelength
conversion device 6D converts the blue light Ls incident from the
light separation element 46 to the fluorescence YL. The wavelength
conversion device 6D has the wavelength converter 62, the hollow
motor 65, the substrate 66, the coupling member 67, the heat
transfer member 68, and the heat radiation member 69, similarly to
the wavelength conversion device 6C.
[0167] In the wavelength conversion device 6C, the substrate 66
supporting the wavelength converter 62 is provided at the face in
the +Z-direction of the rotor pert 651 of the hollow motor 65.
[0168] Meanwhile, in the wavelength conversion device 6D, the
substrate 66 is arranged inside the opening 6511 in the rotor part
651. Specifically, in the wavelength conversion device 6D, the
substrate 66 is circularly formed as viewed from the +Z-direction
and is arranged inside the opening 6511 in such a way that the end
surface of the substrate 66 along the circumferential direction
about the rotation axis Rx is coupled to the inner edge of the
opening 6511.
[0169] Therefore, the wavelength conversion device 6D can be
reduced in dimension along the +Z-direction.
[0170] The above-described projector according to this embodiment
achieves effects similar to those of the projector according to the
third embodiment.
[0171] Also, In the wavelength conversion device 6A according to
the first embodiment, the optical element 61 may be arranged inside
the opening 6511, as in the wavelength conversion device 6D. In
this case, the optical element 61 may be fixed to the inner edge of
the opening 6511 via the attachment member AT or the like.
[0172] Also, in the wavelength conversion device 6B according to
the second embodiment, the substrate 66 may be arranged inside the
opening 6511. In this case, the end surface of the substrate 66
along the circumferential direction about the rotation axis Rx may
be fixed to the inner edge of the opening 6511.
Modifications of Embodiments
[0173] The present disclosure is not limited to the foregoing
embodiments. Modifications and improvements or the like within a
range that can achieve the objective of the present disclosure is
included in the present disclosure.
[0174] In the first embodiment, the hollow motor 65 rotates the
optical element 61 condensing the incident first light onto the
wavelength converter 62. In the second to fourth embodiments, the
hollow motor 65 rotates the wavelength converter 62 and the
substrate 66. However, These are not limiting. The component to be
rotated by the hollow motor 65 may be another optical component
than the optical element 61 and the wavelength converter 62,
provided that the position of incidence of the blue light Ls as the
first light on The wavelength converter 62 can be changed.
[0175] In the first embodiment, the focal point of the optical
element 61 is located on the optical axis X1 of the optical element
61 and at the opposite side or the wavelength converter 62 from the
blue light Ls-incident side. However, this is not limiting. The
focal point of the optical element 61 may be located on the optical
axis X1 of the optical element 61 and at the blue light Ls-incident
side of the wavelength converter 62 or at the wavelength converter
62.
[0176] In the first and second embodiments, the wavelength
conversion device 6A, 6B has the heat radiation member 64 thermally
coupled to the coupling member 63. The heat radiation member 64 as
provided outside the hollow motor 65. However, this is not
limiting. A part of the heat radiation member 64 may be provided in
the hollow space SP provided inside the hollow motor 65. Also, the
entirety of the heat radiation member 64 may be provided in the
hollow space SP. The wavelength conversion devices 6A, 6B may not
have a heat radiation member. In this case, the coupling member 63
may have a plurality of fins. That is, the coupling member 63 and
the heat radiation member 64 may be formed as a unified
component.
[0177] In the second to fourth embodiments, the substrate 66
supported by the rotor part 651 supports the wavelength converter
62, and the substrate 66 and the coupling members 63, 67 are
thermally coupled together. However, this is not limiting. The
substrate 66 and the coupling members 63, 67 may be unified
together.
[0178] In the third and fourth embodiments, the wavelength
conversion device 6C, 6D has the heat radiation member 69 thermally
coupled to the coupling member 67, and the heat transfer member 68
provided between the coupling member 67 and the heat radiation
member 69. A part of the heat radiation member 69 is provided
inside the hollow space SP in the hollow motor 65, and the other
part of the heat radiation member 69 is Provided outside the hollow
motor 65. However, this is not limiting. The entirety of the heat
radiation member 69 may be provided inside the hollow space SP in
the hollow motor 65. Alternatively, the entirety of the heat
radiation member 69 may be provided outside the hollow space SP.
Also, the wavelength conversion device 6C, 6D may not have a heat
radiation member. In this case, the coupling member 67 may have a
plurality of fins. That is, the coupling member 67 and the heat
radiation member 69 may be unified together. In this case, the
plurality of fins may be arranged outside the hollow motor 65.
[0179] In the third and fourth embodiments, the heat transfer
member 68 is a thermally conductive grease provided between the
coupling member 67 and the heat radiation member 69. However, this
is not limiting. The heat transfer member 68 may be a thermally
conductive fluid. That is, the heat transfer member 68 may be
formed of any other material that can thermally couple the coupling
member 67 and the heat radiation member 69 together. Also, the heat
transfer member 68 may be omitted, provided that the thermally
coupled state between the coupling member 67 and the heat radiation
member 69 can be maintained.
[0180] In the third and fourth embodiments, the plurality of
recesses 6921 holding the heat transfer member 68 are provided at
the face 692A facing the coupling member 67, of the heat radiation
member 69. However, this is not limiting. The number of recesses
6921 may be any number equal so or greater than 1. The shape of the
recesses 6921 as viewed from the +Z-direction may be, for example,
spiral. The recesses 6921 may not be provided at the face 692A.
Also, recesses similar so the recesses 6921 may be provided at the
face facing the face 692A, of the coupling member 67, as described
above.
[0181] In the second to fourth embodiments, the rotation axis Rx of
the hollow motor 65 intersects the center of the light incident
surface 622, on which the blue light Ls is incident, of the
wavelength converter 62, as viewed from the blue light Ls-incident
side, the blue light Ls being the first light. However, this is not
limiting. The rotation axis Rx may intersect a part that is not the
center of the light incident surface 622.
[0182] In the embodiments, the wavelength converter 62 has the
wavelength conversion layer 621 and the reflection layer 623.
However, this is riot limiting. The wavelength converter 62 may not
have the reflection layer 623. In this case, the coupling member 63
or the substrate 66 coupled to the wavelength converter 62 may have
a reflection layer.
[0183] The wavelength conversion devices 6A, 6B, 6C, 6D are
reflection-type wavelength conversion devices in which the
wavelength. converter 62 emits the fluorescence YL to the side
opposite to the blue light Ls-incident side. However, this is not
limiting. The wavelength conversion device according to the present
disclosure may be a transmission-type wavelength conversion device
emitting the second light along the direction of incidence of the
first light.
[0184] In the embodiments, the projector has three light modulators
343 (343R, 343G, 343B). However, this is not limiting. The present
disclosure is also applicable to a projector having two or fewer
light modulators or four or more light modulators.
[0185] In the embodiments, the image projection device 3 is
described as having the configuration and layout shown in FIG. 1.
However, this is not limiting. The configuration and layout of the
image projection device 3 are not limited to those described above.
The same can be said of the light source device 4A shown in FIG. 2
and the light source devices 4B, 4C, 4D having a configuration
similar to that of the light source device 4A.
[0186] In the embodiments, the light modulator 343 has a
transmission-type liquid crystal panel where the light incident
surface and the light exiting surface are different from each
other. However, this is not limiting. The light modulator 343 may
have a reflection-type liquid crystal panel where the light
incident surface and the light exiting surface are the same. Also,
a light modulator that does not use liquid crystal, such as a
device using a micromirror, for example, a device using a DMD
(digital micromirror device), may be employed, provided that the
light modulator can modulate an incident luminous flux to form an
image according to image information.
[0187] In the embodiments, the examples where the light source
devices 4A, 4B, 4C, 4D according to the present disclosure are
applied to a projector are described. However, these examples are
not limiting. The light source device according to the present
disclosure may also be employed, for example, for an illumination
device or an automobile headlamp or the like.
[0188] An the embodiments, the examples where the wavelength
conversion devices 6A, 6B, 60, 6D are applied to a light source
device are described. However, these examples are not Limiting. The
wavelength converter according to the present disclosure may also
be employed for other devices than the light source device.
Overview of Present Disclosure
[0189] An overview of the present disclosure is given below.
[0190] According to a first aspect of the present disclosure, a
wavelength conversion device includes: a hollow motor having a
rotation axis and a hollow space; a wavelength converter converting
incident first light in a first wavelength band to second light in
a second wavelength band that is different from the first
wavelength band; and a coupling member thermally coupled to the
wavelength converter. At least a part of the coupling member is
arranged in the hollow space. The hollow motor changes a position
of incidence of the first light on the wavelength converter
relatively to the wavelength converter.
[0191] In such a configuration, the position of incidence of the
first light on the wavelength converter is changed relatively to
the wavelength converter by the hollow motor. Thus, continuous
local incidence of the first light on the wavelength converter can
be restrained. Therefore, the generation of a part with a locally
high temperature in the wavelength converter can be restrained and
a drop in the efficiency of conversion from the first light to the
second light in the wavelength converter can be restrained.
[0192] Since at least a part of the coupling member thermally
coupled to the wavelength converter is provided inside the hollow
space provided in the hollow motor, a path to transfer the heat of
the wavelength converter can be provided inside the hollow space.
Therefore, the wavelength conversion device can be miniaturized,
compared with the case where a path to transfer the heat of the
wavelength converter is provided outside the hollow motor.
[0193] According to the first aspect, the wavelength conversion
device may include an optical element condensing the first light
onto the wavelength converter. An optical axis of the optical
element, an optical axis of the first light incident on the optical
element, and the rotation axis may be spaced apart from each other
on a plane orthogonal to the rotation axis. The hollow motor may
rotate the optical element about the rotation axis.
[0194] In such a configuration, the optical axis of the optical
element, the optical axis of the light incident on the optical
element, and the rotation axis of the optical element by the hollow
motor are spaced apart from each other. Therefore, when the optical
element is rotated by the hollow motor, the position of incidence
of the first light on the optical element changes in a direction
intersecting the optical axis of the first light incident on the
optical element. Thus, the direction of emission of the first light
from the optical element can be changed and therefore the position
of incidence of the first light on the wavelength converter can be
changed. Accordingly, a drop in the efficiency of conversion from
the first light to the second light in the wavelength converter can
be restrained.
[0195] According to the first aspect, the hollow motor may have a
rotor part and a stator part rotating the rotor part about the
rotation axis. The optical element may be supported by the rotor
part.
[0196] In such a configuration, the optical element can be rotated
about the rotation axis of the hollow motor. Also, the optical
element can be easily arranged in such a way that the optical axis
of the optical element and the rotation axis are spaced apart from
each other.
[0197] According to the first aspect, the optical axis of the first
light incident on the wavelength converter may be spaced apart from
the rotation axis on a plane intersecting the rotation axis. The
hollow motor may rotate the wavelength converter about the rotation
axis.
[0198] In such a configuration, the optical axis of the first light
incident on the wavelength converter is spaced apart from the
rotation axis. Therefore, when the wavelength converter is rotated
by the hollow motor, the position of incidence of the first light
on the wavelength converter continuously changes with time in a
circumferential direction about the rotation axis. That is, the
position of incidence of the first light on the wavelength
converter continuously changes with time about the rotation axis.
Therefore, the generation of a part with a locally high temperature
in the wavelength converter can be restrained and a drop in the
efficiency of conversion from the first light to the second light
in the wavelength converter can be restrained.
[0199] According to the first aspect, the wavelength conversion
device may include a heat radiation member thermally coupled to the
coupling member. The heat radiation member may be rotated with the
wavelength converter by the hollow motor. At least a part of the
heat radiation member may be provided outside the hollow motor.
[0200] In such a configuration, the heat of the wavelength
converter can be transferred to the heat radiation member via the
coupling member. Since at least a part of the heat radiation member
is provided outside the hollow motor, the heat of the wavelength
converter can be radiated outside the hollow motor. Also, since the
heat radiation member is rotated with the wavelength converter by
the hollow motor, the radiation of the heat of the wavelength
converter by the heat radiation member can be facilitated. Thus,
the wavelength converter can be cooled effectively.
[0201] According to the first aspect, the wavelength conversion
device may include a heat radiation member thermally coupled to the
coupling member, and a heat transfer member provided between the
coupling member and the heat radiation member. At least a part of
the heat radiation member may be provided outside the hollow
motor.
[0202] In such a configuration, the heat generated in the
wavelength converter can be transferred to the heat radiation
member provided at least partly outside the hollow motor, via the
coupling member and the heat transfer member. Thus, the heat of the
wavelength converter can be radiated outside the hollow motor.
Therefore, the wavelength converter can be cooled effectively.
[0203] According to the first aspect, the heat transfer member may
be a thermally conductive grease.
[0204] In such a configuration, the heat of the wavelength
converter can be transferred from the coupling member to the heat
radiation member via the heat transfer member even when the heat
radiation member it fixed. Thus, the heat of the wavelength
converter can be efficiently transferred to the heat radiation
member.
[0205] According to the first aspect, the heat radiation member may
have a recess that is provided at a face facing the coupling member
and that holds the heat transfer member.
[0206] In such a configuration, the state where the heat transfer
member is held between the coupling member and the heat radiation
member can be maintained. Thus, the thermally coupled state between
the coupling member and the heat radiation member can be
maintained.
[0207] According to the first aspect, the wavelength conversion
device may include a substrate supporting the wavelength converter.
The hollow motor may have a rotor part and a stator part rotating
the rotor part about the rotation axis. The substrate may be
supported by the rotor part.
[0208] In such a configuration, the wavelength converter can be
rotated about the rotation axis of the hollow motor.
[0209] According to a second aspect of the present disclosure, a
light source device includes: the wavelength conversion device
according to the first aspect; and a light source emitting the
first light incident on the wavelength conversion device.
[0210] Such a configuration can achieve effects similar to those of
the wavelength conversion device according to the first aspect.
Thus, a light source device that can stably emit light can be
formed.
[0211] According to a third aspect of the present disclosure, a
projector includes: the light source device according to the second
aspect; a light modulator modulating light emitted from the light
source device according to image information; and an optical
projection device projecting the light modulated by the light
modulator.
[0212] Such a configuration can achieve effects similar to those of
the light source device according to the second aspect. Thus, a
projector that can stably project light can be configured.
* * * * *